# array of 64 chars to encode 6 bits. this is almost like base64 encoding, but
# the symbolic chars are different, as base64's + and / aren't very
# URL-friendly.
- ARRAY = ('A'..'Z').to_a + ('a'..'z').to_a + ('0'..'9').to_a + ['_', '~']
+ ARRAY = ("A".."Z").to_a + ("a".."z").to_a + ("0".."9").to_a + ["_", "~"]
##
# Given a string encoding a location, returns the [lon, lat, z] tuple of that
# keep support for old shortlinks which use the @ character, now
# replaced by the ~ character because twitter is horribly broken
# and we can't have that.
- str.gsub!("@", "~")
+ str.tr!("@", "~")
str.each_char do |c|
t = ARRAY.index c
# given a location and zoom, return a short string representing it.
def self.encode(lon, lat, z)
code = interleave_bits(((lon + 180.0) * 2**32 / 360.0).to_i,
- ((lat + 90.0) * 2**32 / 180.0).to_i)
+ ((lat + 90.0) * 2**32 / 180.0).to_i)
str = ""
# add eight to the zoom level, which approximates an accuracy of
# one pixel in a tile.